Stitch-forming mechanism for sewing machines



I. R. IVIOFFATT.

STITCH FORMING MECHANISNI FOR SEWING MACHINES. APPLICATION FILED IULYIB,1917.

1,405,855. PatentedFeb. 7, 1922.,

6 SHEETS-SHEET I- J. R. MOFFATT.

APPLICATION fILEI) JULYI8. 19|?.

STITCH FORMING MECHANISM FOR SEWING MACHINES.

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1. RfMoFF/W. STITCH FORMING MECHANISNI FOR SEWING MACHINES.

IMPLICATION FILED JULYIB. 19H. Patented 7 s lsmilaTs-smnz s.

J. R. MOFFATT. STITCH FORMING MECHANISM FOR SEWING MACHINES.-

Patented Feb. 7, 1922.

6 SHEETS-SHEET 4- APPLICATION FILED JULYIB. 1917.

` J. ramon/IIT.'

STITCH FORMING MCHANISM FOR SEWING' MACHINES.

rammed Feb. 7, 1922.

`.I\PPLICATION FILED IULYIB, I9I7- 6 SHEETS-SHEET 5- J. R. MOFFATT.

STITCH FORMING MECHANISM FOR SEWING MACHINES. APPLICATIONrILEDIIILYIs.I9I1.

` 1,405,855, rammed Feb.7,1922.

6 vSHEETS-SHEET 6.

UNITED STATES PATENT oFFlCE- JAMES R. MOFFAT'I, CHICAGO, ILLINOIS,ASSIGNOR T0 UNION krSPIECIAI'.' MACHINE COMPANY, OF CHICAGO, ILLINOIS, ACORPORATION F ILLDTOIS. n

STITCH-nomme MECHANISM FoasEwiNG MACHINES.

- v Application led J`u1y'18,

To all whom 'it may concern.'

Beit known that I, JAMES It. MoiFA'r'r, a citizen of vthe United States,Vresiding at Chicago, in the county of Cook, State of. Illinois, haveinvented certain new and useful Improvements in Stitch-Forming" Mech,- f

anism for Sewing Machines, of which the following is a description,reference being` had to the accompanying drawing and to the figures ofreference marked thereon.

Theinventionrelates to new anduseful improvements in stitchlformingmechanisms for sewing machines, and more particularly to the mechanismfor laying a crossthread between and connecting needle threads on theupper surface of the fabric.

An object of the invention 1 character having a thread-hook for engagingthe cross-thread and forming a loop therein, and with a stationaryVfinger against which the cross-thread is drawn bythe hool These andother objects w1 fully disclosed. In the drawings',- Figure l is a frontview of a sewing machine embodying my improvements and hav-v ing a partthereof broken away to show the loop'er; A

Figure 2 is an enlarged front view of the end of the sewing machine withthe edging guide removed;

Figure Sis an end view of the machine, showing the parts at the end ofthe overhanging arm, the overhangingarm being omitted;

Figure isV a view partly in top plan and'partly in section, the sectionbeing taken directly beneath the lower bearing ofthe cverhanging arm; l

Figure 5 is a perspective view showing the' needles, the thread-hook,the thread nger and the thread-'guides forthe cros^- thread, thehook'being at the forward end of its stroke; Figure 6 is a plan Viewshowing the Athread s to provide ,y a stitch-forming mechanism oftheabove llA in part y'be obvious and willin part be hereinafter morey1917; Serial No.. 1"s1,2os.

specification of Lettersrat'enf. Patented' Feb. 7,1922,

forward -end of its stroke;,` and also show ing the fabric, theedgingand the interf.

'v 60 Figure 7 is a'view similar to. Figure 5,

chained cross-threadand needle-threads;

but showing a slightlyl modified form". of stationary thread-finger; v

Figure 8 is av plan Vview showing the thread-hook, thethrea'd-finger andthe fixed thread-guides for the cross-thread;

Figure 49sis a AView similar,V to Figurej,vv

but showingthe hook at'the rear end 'of its stroke and as about toengage'the cross- Figure 10 is a 'diagrammatic view, showing therelation of the threads to the fabricv 'n and the edging.

The invention is embodied 'in' astitching y mechanism consisting of aplurality' of needles whichv are arranged abreast andwith which a singlelooper co-operates beneath` the Work support. (lo-operating vwith theseneedles above the work support is a crossthread-laying hook adapted toengage a cross-thread and form a loop therein for one of the needles toenter.,

Associated with the Vcross-thread-l'aying Vhook is a finger againstwhich the cross# thread is drawn, and this finger is so shaped that thepull of the hook on the cross-thread will cause the cross-thread 'toslide( rear Wardly on the finger and be positioned between the needles.Also associated with the finger and the cross-thread-laying hook is aneedle bar, through Vwhich the cross-thread extends, andthisthread-guide on its .downward movement serves to bring the lcrossthreadto its forward position on the' threadfingerwhere it willbe engaged bythe hook thread-guide movable up and down with the as it next movesyforward to form a loop.

Referring more'in detail to the drawings, my improved stitch-formingmechanismis shown as applied to a sewing machine having a work support1, an overhanging arm 2 in which reciprocates a needle bar 3, carrying apair of needles 4 and 5; (3o-operating with the needles 4f and 5 beneaththe work support' is a threaded looper 6. Said looper is pivoted at 7and is oscillated by alink 8. This link 8 is pivoted at its other end tothe needle lever extension 9 carried bythe needle lever l0.

c The needle lever 10 is connected by a link l1 to the needle bar@ Theneedle lever is'oscillated by the eccen Y triclstrap 12 which,eo-operateswith the eccentric on the main shaft, and the main shaft isrotated by the usual belt wheel'13.

The material is held on the worksupport by a presser foot 14 carried bya presser bar 154 mounted in the overhanglng arm. The

. needle 4 is provided with a needle-thread 4,

while the needle is provided with-a needlethread 5a. Theseneedle-threads pass through a suitable/'guide 16 "at thejupper end ofthe needle bary and valso through guides17 and 18 on the needle lever.Said threads between the guidesl and 18 pass through a threadingmechanism described, are of the well cross-thread is led Vfrom atension21 through spaced guides`22, 22; and thence through a fixed thread-guide23 formed in an arm 24 guide 19. Y These thread-guides and thestitchknown construction and further .detail de `scription thereof isnot fthought necessary.

The needles pass down through the fabric vand the looper enters,` boththreaddoops formed by the needles, and the looper-thread is therebyconcatenated'` with both needlethread loops. j p The needle-threads arejoined on the upper face of the fabric by a cross-thread 20. Thissecured to a bracket 25 attached to the overhanging arm of the machine.vAn arm 22` carried by the needle bar .engages the crossthread betweenthe guides 22, 22 for pulling,

offthe cross-thread.

Mounted on the needle bar d3 is an arm 26 havinga thread-eye 27.- Thecross-thread passes through thisvthread-eye; Thecross'- thread is formedinto loops by a thread-hook 'y means of screws 33, 33.L The lever. 32extends to lthe rear of the overhang-ing' arm, 'and is 28.v vV'1`histhread-hook is formed with'a notched end 29 and-with a shank 30,which' extends vertically vthrough a sleevel carried by a lever orfthread-hook carrier 32. The shankO is adjustably held in the sleeve: by

pivotally supported by the bracket 25.l Said brackethas'spaced earscarrying a vertical i shaft 34, to which the lever 32 is secured. Y Thelever32 is'provided with a ball stud 35 and a link 86bis pivotallyattached to this vball stud. j The link 36 at itsother end is piv-:otally connected at 39 to a bracket 40 carried at the lower end of theneedle lever extension 9. As the needle lever extension oscillates, thelever 32 will be oseillated, and thiswill move' the vthread-hook backand forth across lthe line of feed, or across a vertical plane passingcentrally between theneedles.

.the needles.

"which the. screws extend are elongated ver- Y itically, so thearm 42maybe raised and,

lowered slightly.

The thread-finger 41, asV sho-wn in the drawings, is provided with aslot 43. The wall 44 of this slot is, however, the only active .surfaceagainst which the threadvis moved. As clearly shownY in the drawings,

thissurface is shownas yconsisting of a concave. curved surf-ace, whichleads into a convex curved'surface, the convex curved surface formingtheV curved shoulder 45.-

V'Vhen the needles are clear down, as indicatedin Figure 9 0f thedrawings, the

thread-hook is at the extreme rear end of its stroke. The threadeguide27l for the cross-thread is at the lower end of its stroke' 'and is sodisposed relative to the linger 41 as to draw thecross-thread vforwardon the finger to a point adjacent the forward .Vendi Whenthecross-thread is thus of the slot. j y positioned, as the hook movesforward, Yit

. engages the cross-threadQ- That is to say,

thenotch in the thread-hook moves-underneath the finger at thel forwardend of the curved slot. After the' hook has engaged the cross-thread, itforms the crossthread yinto a looprin the well known way, which loopwil-l be entered bythe needle farthest from the thread-finger. It isalso desirable that the cross-thread should pass4 between As the hook;moves forward,

it pulls the cross-threadaigainst this threadfinger andthe guide .27moving upwardly away fromthe finger, permits the pull on along thefinger.

the thread to draw the thread rearwardlyV Inasmueh as `the finger isconcaveat the `forward end thereof, the thread will be given up quicklyandV easily to the hook. Just as the-.thread is reaching the rear end ofits movement along the finger, it slides along the convex curvedshoulder 45 and this takes any slack out` of the thread, so it will be.held taut by the hook needles are past the thread.

When the cross-thread reaches this position, as clearly shown in Figure5, the

needles will Ypass down, one on each side of the thread between thenotch in the hook and the thread-finger, and the left hand needle orneedle 4 will enter the threadloop formed in the cross-thread. vWhen thethread-hook returns, the loop is dropped, and the movable thread-eye onthe Vneedle until the bar will draw thecross-thread again to the forwardend of the slot. y Y

In Figure 7 of thedrawings I have shown a slightly modified form ofthread-finger 4l. In this form of thread-finger therev is no slot, butthe surface 44 isshaped substantially as above described andthecrossthread slides along this surface. The

thread-hook may be adjusted vertically and also the thread-finger may be.adjusted vertically, to bring 4these parts intoproper 'co-operativeposition relative tothe needles.

thence through a guiding device 47; and

thence Jaround av guiding roller 48, carried by the presser foot. Theedging is directed so as tov slightly'overlap the edges' of the fabric.The needles 4 and 5 both penetrate'- certainty. 1

the fabric and the needle 5 passes through the edging. nected below ybythe looper thread, and are connected .abovey 'by the cross-thread, andthe cross-thread thus firmly secures and covers'the edge portion of theedging where it is joined to the fabric. i

F rom the above description', Lit will be apparent that I have provideda crossthread-laying mechanism in which the crossthread is positivelyhandled by a minimum number of movable parts, and, therefore,

there is little or no wear on the cross-thread and it will be laid withcertainty relative to the needles.

It is obvious that minor changes in the details of the construction maybe made, without departing from the spirit of the invention as set forthin the appended claims.

Having thus described my invention, what I claim as new and desire tosecure by Let-- ters Patent, is:

l. The combination with Va plurality of needles and complementalstitch-forming mechanism, of a thread hook for forming a loop in a crossthread for certain of said needles to enter, means against which thecross thread is drawn by the hook, said means being shaped so that, asthe cross thread is forced against the same by the hook, said crossthread will move rearwardly while in engagement with said means andposition p one strand of the loop between the needles.

2. The combination with a plurality of needles and complementalstitch-forming mechanism, of a thread hook for forming a loop in a crossthread for certain of said needles to enter, a thread finger againstwhich the cross thread is drawn by the hook, said linger being shaped sothat, as the cross thread is forced against said thread finger by thehook, said cross thread will move lrear'- wardly while in engagementwith said thread finger and position one strand of the cross threadbetween the needles.

3. In cross threadflaying mechanism, thev combination with a pluralityof needles and complemental stitch forming mechanism, of

,a feeding mechanism, a reciprocatory thread hook for forming loops in across thread for one of said needles to enter, means for operating saidhook, a guide for the cross thread The needle-threads are lcondisposedin a' position -above the vpath vof movement of :thefree end of the hookand voperatingto position the thread infront of the; hook so thatsaid-hook ywill engage the thread withv certainty, and means; againstwhich one strand'of the loop is carried byy the forward movement of saidhook whereby said vstrandLwill be positioned between the f'-needles,-and'feeding mechanism operating .to

rearwardlymove the other strand'of the loop 1 whereby-the needlefarthest removed from the lloop with said thread guide will enter 4;'The 1 combination with ay plurality of needles f and complementalkstitch-forming mechanism, of-afthread-hook for forming a loop'in across-thread for one of saidneedles toenter, Vand" a fixed.thread-finger against which the cross-thread isk drawn, said fingerhaving a curved surface disposed relative to the movement of the hook,so that the pull ofthe hook will cause the thread to move backward onthefinger and be properly positioned relative tothe needles. p

5. The combination with a plurality of needles and complementalstitch-forming mechanism, of a thread-hook for forminr a loop in across-thread for one of the needles to enter,a vertically movable guidefor the cross-thread, a stationary finger against which the cross-threadis drawn by the hook, said finger being shapedvso as to move the threadrearwardly to properly position the same relative to the needles as thehook pulls out the thread, and said thread-guide being so positioned asto return the cross-threadto the forward end of the linger forengagement by the hook on its next forward movement.

6. The combination with a plurality of needles and complementalstitch-forming mechanism, of a thread-hook for forming a loop in across-thread for one of said needles to enter, a fixed thread-fingerhaving a curved face against which the cross-thread is drawn by thehook, said curved face operating to move the thread rearwardly as thehook.` pulls on the thread, the forward portion ofthe curved faceagainst which theV curved face against which the cross-thread is drawnby the hook, said curved face operating to` move the thread rearwardlyas the hook pulls on the thread, the forward portion of the curved faceagainst which the thread is pulled by the hook being concave and therearward portion against which the thread isYdrawn-being convex, saidconvex surfacek co-operating with the hook to pull lthe thread taut, anda vertically movable thread-guide forthe cross-thread, said verticallymovable thread-guide vbeing positionedso as to move the thread forwardVon said finger when released by the hook into position to be engaged bythe hook on its next forward movement. 5

' 8. `The combination with a needle bar, a plurality of needles andcomplemental; stitchforming mechanism, of a thread-hook for forming aloop in a cross-thread for one of V the needles to enter, a stationaryfin er against which tliecrossthread isdrawnA y vthe hook, said fingerbeing shaped so as to move the crossthread rearwardly as the threadv ispulled thereagainst--by the hook aV thread-guide Carried by theneedle-bar or said cross-thread, said thread-guide being-.so lpositioned that inits vertical movements said-tliread-guide ,Will4movefth'e thread forl iva-rd on tliejlinger when released by the hook.and yposition ythe same for engagement by the;`

hook on its next forward movement.Y Y'

9. The combination .of a plurality Y of needles, a eross-tliread-layinghook, a fixed thread-linger. (3o-operating With said crossthread-layingf hook, la .i lever for ysupporting levier, Wherebytlie samemay beadjusted vversaid hook, said hook being,attachedV to said tically, andmeans for supporting said fixed f tliread-ingerrwhereby it bevertically" adj-usted;

In testimony whereof', I aiiix my signature

